Dao-Xin Yao

Orbital-weight redistribution triggered by spin order in the pnictides

The one-particle spectral function and its orbital composition are investigated in a three-orbital model for the undoped parent compounds of the iron-based superconductors. In the realistic parameter regime, where results fit experimental data best, it is observed that the magnetization in the

Neutron and ARPES constraints on the couplings of the multiorbital Hubbard model for the iron pnictides

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Spin waves and magnetic exchange interactions in the spin-ladder compound RbFe 2 Se 3

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Charge stripes in the two-orbital Hubbard model for iron pnictides

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Criticality and Mott glass phase in a disordered two-dimensional quantum spin system

orbitals are markedly different and the Fermi surface presents mostly

Spectrum splitting of bimagnon excitations in a spatially frustrated Heisenberg antiferromagnet revealed by resonant inelastic x-ray scattering

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Spin Waves and Spatially Anisotropic Exchange Interactions in the S = 2 Stripe Antiferromagnet Rb0.8Fe1.5S2

character, as recently observed in photoemission experiments [T. Shimojima et al., Phys. Rev. Lett. 104, 057002 (2010)]. Since the ferro-orbital order in this regime is at most a few percent, these results are mainly driven by the magnetic order. An analogous analysis for a five-orbital model leads to similar conclusions.

Magnetic state of K0.8Fe1.6Se2 from a five-orbital Hubbard model in the Hartree-Fock approximation

The results of neutron-scattering and angle-resolved photoemission experiments for the Fe-pnictide parent compounds, and their metallic nature, are shown to impose severe constraints on the range of values that can be considered realistic for the intraorbital Hubbard repulsion U and Hund coupling J in multiorbital Hubbard models treated in the mean-field approximation. Phase diagrams for three- and five-orbital models are here provided, and the physically realistic regime of couplings is highlighted, to guide future theoretical work into the proper region of parameters of Hubbard models. In addition, using the random phase approximation, the pairing tendencies in these realistic coupling regions are investigated. It is shown that the dominant spin-singlet pairing channels in these coupling regimes correspond to nodal superconductivity, with strong competition between several states that belong to different irreducible representations. This is compatible with experimental bulk measurements that have reported the existence of nodes in several Fe-pnictide compounds.

Mott glass phase in a diluted bilayer Heisenberg quantum antiferromagnet

Author(s): Wang, M; Yi, M; Jin, S; Jiang, H; Song, Y; Luo, H; Christianson, AD; De La Cruz, C; Bourret-Courchesne, E; Yao, DX; Lee, DH; Birgeneau, RJ | Abstract:

Detecting Crystallographic Lattice Chirality using Resonant Inelastic X-ray Scattering.

The two-orbital Hubbard model for the pnictides is studied numerically using the real-space Hartree Fock approximation on finite clusters. Upon electron doping, states with a nonuniform distribution of charge are stabilized. The observed patterns correspond to charge stripes oriented perpendicular to the direction of the spin stripes of the undoped magnetic ground state. While these charge-striped states are robust when the undoped state has a Hubbard gap, their existence when the intermediate-coupling magnetic metallic state of pnictides is doped was also observed for particular model parameters. Results for hole doping and implications for recent experiments that reported electronic nematic states and spin incommensurability are also briefly discussed.